— Who's ___________?
— He's my uncle. [ ]
A. he
B. she
C. it
答案：A
— What is your sister?
— She is _________. [ ]
A. beautiful
B. a student
C. at home
D. doing her homework
哪项不属于物联网的应用难点（）
A、技术标准问题
B、数据安全问题
C、计算能力问题
D、IP地址问题
